高效液相荧光法测定“北京烤鸭”鸭皮中的多环芳烃

Determination of Polycyclic Aromatic Hydrocarbons in Skin of "Peking Roast Duck" by High Performance Chromatography-Fluorescence Detection

采用气体射流冲击加热新技术烤制"北京烤鸭",对其烤制过程中可能产生的三种多环芳烃(PAHs)含量进行检测,建立一套适合于烤鸭类高脂肪、高蛋白食品中PAHs的提取与检测的方法。方法:匀浆鸭皮样品前处理采用2mol/LKOH甲醇-水(8:2,V/V)皂化,异辛烷萃取,甲醇-水(1:1,V/V)洗涤,N,N-二甲基甲酰胺-水-异辛烷(1:1:1,V/V)反萃取和Florisil固相萃取小柱净化,最后进行HPLC分析。结果:标品实验回收率在83.59%～92.97%,当样品加标水平分别为1、2、2μg/kg时,回收率在73.85%～80.31%,RSD<10%,三种PAHs检测量在0.56～3.19μg/kg。结论:该方法净化效果较好,重现性高,检测灵敏度和准确度均满足分析要求,样品中苯并[a]芘的含量远远低于国家规定对烟熏烧烤类食品不能超过5μg/kg的标准。

In the process of ＂Peking Roast Duck＂ with a novel heating technique, namely air jet impingement, polycyclic aromatic hydrocarbons （PAHs） may be formed. A method of HPLC coupled with fluorescence detector was developed for the determination of PAHs in fat- and protein-rich foods, such as ＂Peking Roast Duck＂. Homogenized duck skin samples were pretreated by using methanol containing 2 mol/L KOH-water （8：2, V/V） for saponification, issoctane for extraction, methanol- water （1：1, V/V） for washing, DMF-water-issoctane （1：1：1, V/V） for liquid-liquid partition, and Florisil solid-phase column for cleaning up. Results showed that the recoveries of benzo[a]pyrene （B[a]P）, dibenzo[a,h]anthracene （DB[a.h]A） and 7,12- dimethylbenzene[a] anthracene （7,12-DMB [a]A） in blank sample at the spiked amounts of 2 × 10^-8 and 1 × 10^-7 g were between 83.59% and 92.97%, and their recoveries at the spiked amount of 1, 2 and 2 μg/kg respectively, were 73.85% to 80.31%, and the RSDs were less than 10%. Their contents in roasted duck ranged from 0.56 to 3.19 μg/kg, but no these three compounds were found in raw duck. Our results suggested the high clean-up efficiency and recovery of this method and the sensitivity and accuracy of detection could meet the requirements for analysis of trace compounds in complex matrices. The B[a]P content of 0.56 μg/kg is far less than the maximum limit value of 5μg/kg in the smoked and roasted foods in term of the national standards.